Neurotrophin-3 (NT-3) levels in the developing rat nervous system and in human samples.

We developed an enzyme immunoassay (EIA) system for neurotrophin-3 (NT-3), based on a biotin-streptavidin detection system capable of measuring concentrations as low as 0.5 pg/ml with high reproducibility. We measured NT-3 levels in the developing rat nervous system as well as in normal subjects and patients with Alzheimer's disease (AD). The developmental change of NT-3 level in rat brain and peripheral tissues coincided with the change in NT-3 mRNA level reported before. We could not find any differences in NT-3 level in serum, cerebrospinal fluid, or brain (hippocampus and parietal cortex) obtained from controls and patients with AD.